Fabric stretching and/or alternatelyreversing mechanism for separating fabric pieces from a stack thereof



3,355,165 -HEVEBSING MEG Nov. 28. 196 w. F. SOUTHWELL ETAL F'ABH l CSTRE'I'CHINU AND/0R ALTERNATELY HANISM FOR SEIA RATING FABRIC PIECESFROM A STACK THEREOF Filed April 20, 1965 7 Sheets-Sheet 1 INVENTORSWYNDHAM F.SOUTHWELL NICHOLAS WEHRMANN ATTORNEYS Nov. 28. 1967 W. F.FABRIC S'IRETCHING AND/OR AIJTERNATELJY FOR SEPAHATING FABRIC PT FiledApril 20, 1965 7 Sheets-Sheet FIG.

FIG. 3

ullmlh u INVENTOR WYNDHAM E SOUTHWELL NICHOLAS WEHRMANN J 777, M M,ATTORNEYS v- 1967 w. F. SOUTHWELL ETAL 3,355,165

FABRIC STRETCHING AND/0R ALTERNA'I'ELY"REVERSING MECHANISM FORSEPARATING FABRIC PIECES FROM A STACK THEREOF Filed April 20, 1965 7Sheets-Sheet 3 INVENTORS WYNDHAM F. SOUTHWELL NICHOLAS WEHR MANN Nov-28. 1967 w. F. soumwsu. ETAL w 3,3 I FABR 1C STRETCHING AND/ORALTERNATELYREVERSING MECHANISM FOR SEPARATING FABRIC PIECES FROM A STACKTHEREOF Filed April 20, 1965 7 Sheets-Sheet 4 FIG. 6

95 IOIEF] AIR IN INVENTORS WYNDHAM F SOUTHWELL NICHOLAS WEHRMANN ATORNEYS Nov. 28. 1 w. F. SOUTHWELL ETAL 3,355,165

FABRLC STRETCHING AND/OR ALTBRNATELYREVERSING MECHANISM FOR SEPARATINGFABRlC PIECES FROM A STACK THEREOF Filed April 20, 1965 7 Sheets-Sheet 5INVENTORS WYNDHAM F. SOUTHWELL NICHOLAS WEHRMANN ATTORNEYS Nov. 28. 1967F. SOUTHWELL ETAL 3,355,165 FABRIC STRETCHING AND/ORALTERNATELY-REVERSING MECHANISM FOR SEPARATING FABRIC PIECES FROM ASTACK THEREOF Filed April 20, 1965 7 Sheets-Sheet 6 FIG. 9

79G 79 SB LSA m I33 B1 LS LSA2 FIG. 11

LSB2 205 LSA2 265 270 INVENTORS WYNDHAM F. SOUTHWELL BY NICHOLASWEHRMANN ATTORNEYS United States Patent 3,355,165 7 FABRIC STRETCHINGAND/OR ALTERNATELY- REVERSING MECHANISM FOR SEPARATING FABRIC PIECESFROM A STACK THEREOF Wyndham F. Southwell, Wilkeshoro, and NicholasWehrmann, North Wilkesboro, N.C., assignors to L & L Manufacturing,Inc., a corporation of Delaware Filed Apr. 20, 1965, Ser. No. 449,460 12Claims. (Cl. 27112) This invention relates to means for separatingfabric pieces from a stack thereof, and has for its objects theprovision of such mechanism which is particularly arranged forovercoming the natural tendency of stacked fabric pieces to cling toeach other and which, for example, may form a part of means forwithdrawing fabric pieces one-by-one from the top of a stack thereof;and, independently of or in combination with the foregoing, of grippingmechanism adapted to pick up and withdraw fabric pieces one-by-one froma stack thereof but in such a manner that certain, but not all, of themmay be deposited with a different side up than the side which wasuppermost in the stack.

We have found that the tendencies of a fabric piece to cling to a fabricpiece next below it may be overcome with great ease and certainty bymechanism including 1 means to engage the upper surface of the top pieceof a stack toward each of opposite edges of the piece and means to movean engaging portion of at least one of said means toward its respectiveedge so as to stretch the fabric therebetween, and thereby displace theuppermost piece generally horizontally thruout most of its extent, forexample; this displacement serving to positively break the clingingaction of the two pieces thruout most of their area of contact, and thusgreatly assisting the separation of the uppermost piece. In certaininstances, if desired, any undissipated clinging tendency which remainsafter the stretching may be broken as by an air blast. The inventionfinds a veryimportant application in the separation of pieces of knittedfabric from a stack thereof.

We have also found that the reversal of certain of the pieces beingseparated from a stack (as, for example alternate pieces in a stackformed by cutting a stack of tubular fabrics interiorly of its edges sothat a particular face of the upper-most piece is up whereas thecorresponding face of the next piece is down) can be performed with ahigh degree of effectiveness by mechanism wherein the .timing of therelease operations on picked-up sheets is varied depending on the orderof different sheets in a stack.

Particularly satisfactory results in both instances may be obtained bymechanism comprising at each side thereof one of a pair of grippingelements, and the invention in its more specific aspects contemplatesthe provision of such mechanism for both purposes. A particularlysatisfactory form of gripping elements are elements rotatable onparallel axes and having convex axially-extending frictional surfacesadapted to be pressed against the upper fabric piece of a stack andthere rotated.

Such elements may be carried on a single head, and means may be providedto cause relative separative movement between such a head and astack-support as by means such as exemplified herein or means asexemplified in our copending application Ser. No. 412,103 filed Nov. 18,1964.

The invention accordingly comprises the features of construction,combination of elements, and arrangements of parts, which will beexemplified in the constructions hereinafter set forth and the scope ofthe application of which will be indicated in the claims.

ice

For a fuller understanding of the nature and objects of the invention,reference should be had to the following detailed description taken inconnection with the accompanying drawings, in which:

FIGURE 1 is a perspective view of one form of mechanism embodying theinvention;

FIG. 2 is a view of the lefthand portion of the opposite side thereof;

FIG. 3 is a top view of the portion of the mechanism shown in FIG. 2;

FIG. 4 is a sectional View on an enlarged scale on the line 44 of FIG.3;

3 FIG. 5 is a similar view along the line 55 of FIG. FIG. 6 is ahorizontal section on the line 6-6 of FIG.

FIG. 7 is a diagrammatic showing of the air pressure control means;

FIG. 8a is a schematic view of the pick-up head in pick-up position atthe beginning of a first cycle of operations;

FIG. 8b shows the pick-up head beginning to move a fabric piece over thebafile plate;

FIG. shows the pick-up head after the release of the forward portion ofthe piece onto the conveyor when the forward gripping means is stillabove the conveyor, altho on its way back to pick-up position;

FIG. 8d shows the pick-up head just after the release of the rearportion of the fabric piece for forward movement by the conveyor;

FIG. 8e shows the pick-up head in position at the beginning of a secondcycle of operations for picking up a piece of material which, before thecutting on the stack, formed the lower half of a piece of tubularfabric;

FIG. 8 ShOWs the pick-up head in the process of removing the secondpiece of fabric;

FIG. 8g shows the pick-up head after the release of the forward portionof the fabric before the pick-up head has reached the conveyor;

FIG. 8h shows the pick-up head moving the fabric over the baflie plateso as to turn it over prior to the release of the rearward grippingmeans;

FIG. 8i shows the gripping head over the conveyor just after therearward gripping means has released its end of the fabric;

FIG. 8i shows the just-released fabric piece being moved forward in aposition on the conveyor following the piece which was previously pickedup and deposited;

FIG. 9 is a perspective view showing the operating cam arrangement at atime when the beam is in the position of FIG. 8a in the first cycle;

FIG. 10 is a detail View on an enlarged scale of one of the operatingcam arrangements;

FIG. 11 is a diagrammatic view showing the timing of the operationsinvolved at a time when the beam is in the position of FIG. 8a in thefirst cycle; and

FIG. 12 is a circuit diagram.

In the form of apparatus exemplified, there is provided a framegenerally designated by the numeral 10. A beam 12 is swinginglysupported by shaft 13 journalled to the frame. Mounted on the shaft 13and fixed to the frame 10 is asprocket 14 over which there extends achain 15 extending to a sprocket 16 fixed on a shaft 17 rotatablysupported from a cross-piece 18 near the free end of the beam 12. Fixedto the shaft 17 is an operative head 20 which, due to the provision ofthe chain and its sprockets, is caused to turn with respect to the beamand is thus prevented from turning with respect to the floor when thebeam is swung. The head 20 will thus have its lower side down and willbe in the same relationship to the earths gravity at all times, so as topick up a fabric piece, transport it, and release it while the fabricpiece hangs below the head.

To the beam there is fixed a crank arm 22 to which is pivoted one end ofa link 23 the other end of which is pivoted to the end of a crank arm 24which is fixed to a shaft 25, the etfective lengths and relations-hipsof the elements 22, 23, and 24 being such as to move the beam 12 andhead 20 to carry the head 20 between an operative position X and arelease position Y (FIGS. 1 and 2). The shaft 25 is driven, by meansincluding a speed-reduction means 26, a speed-control means 27; a belt28 and a pulley 2811, at a constant predetermined speede.g. ten tothirty (preferably eighteen) revolutions per minute from a motor 29 bytransmission means including a belt 30 running on pulleys 31 and 32. Inthe present instance there is employed a one-third horsepower motor.

The operative head 20 (which in the exemplified form of constructionserves as a pick-up head) carries, respectively, at two positions spacedfrom each other and differently spaced from the shaft 13 when in pick-upposition, a gripping means 33 and a gripping means 34 (which in theexemplified form of construction are in the form of pick-up means)adapted to engage and be pressed against the uppermost fabric piece 38of a stack 39 of (in the present instance) single-ply fabric pieces cutfrom a stack of tubular knitted fabric. In the present instance, thegripping means 33 is so positioned as to engage the fabric piece 38 nearone edge thereof (the edge furthest from the shaft 13 in the presentinstance), and the gripping means 34 is so positioned as to engage thefabric piece 38 near the opposite edge thereof (the edge nearest theshaft 13, in the present instance); it being important, when grippingmeans 33 and 34 are utilized to overcome tendencies of the fabric piece38 to cling to the fabric piece 40 below it by stretching the fabricpiece 38 between them, that as great a proportion of the fabric aspractical lie between the gripping means 33 and the gripping means 34.

The stack 39 is carried by a support table 41; and a foam rubber cushion42 or the like is preferably provided between the two.

As exemplified, the gripping means 33 comprises a rotatable element 43adapted to contact the uppermost piece of fabric on the stack 39 nearthat edge of the stack which is furthest from the shaft 13, and thegripping means 34 comprises a rotatable element 44 adapted to contactthe same uppermost piece of fabric near the opposite edge of the stack(which is nearest to the shaft 13), and there is provided means to movethe fabric-contacting portions of the elements 43 and 44 away from eachother. To this end, the element 43 is formed with a pinion 47 meshingwith a rack 48, and the element 44 is formed wit-h a similar pinion 49meshing with a rack 50, and solenoids 53 and 54 are provided to drawthese racks toward each other. Oppositely-acting solenoids 55 and 56 areprovided to move them away from each other. The solenoids 53 and 54,respectively, rotate the elements 43 and 4-4 sufficiently to move thelower surface portions 57 and 58 thereof away from each other when theyare in engagement with the uppermost piece of fabric and to draw theengaged portions of this piece of fabric apart and to break, to a verygreat extent, its tendency to cling to the piece below it.

In order to assure a positive separative action of the elements 43 and44 and to provide for a pick-up action thereby, the surface portions 57and 58 are formed as friction surfaces, as by providing sandpaper onthose portions (or, as exemplified, on the entire peripheral surfaces ofthe cylinders which constitute the elements 4-3 and 44). Sandpaper ofvarious grades may be used. Papers carrying silicon carbide abrasive ofthirty grit, sixty grit, one hundred grit and five hundred grit, andalumina abrasive of thirty-six grit and one hundred and fifty grit have,among others, given satisfactory results. In general it may be statedthat the coefficient of friction between the operative surface of thepick-up element and the particular fabric pick up should be greater thanthe coefficient of friction between two layers of fabric.

While in some instances the friction surfaces of pick-up elements suchas 43 and 44 will be all that is needed to assure the picking up of theportions of the fabric which are engaged thereby, it is very importantin certain instances, and desirable in others, that the fabric bepositively pinched as an initial or other part of the pick-up action. Tothis end the gripping means 33 and 34 as exemplified are formedrespectively with pinching elements 59 and 60 respectively whichprovide, respectively, surfaces 61 and 62 toward which the surfaces 57and 58 move when the elements 43 and 44 are rotated to stretch thefabric, to draw portions of the fabric into the space between thesurfaces 57 and 61 at one side and between the surfaces 58 and 62 at theother side, and to pinch these fabric portions suificiently so as toassure that they will be positively held by the gripping means 33 and 34until the individual release of each individual gripping means (or thejoint release of the two gripping means if so desired).

In order to energize the solenoids 53 and 54 there are providedelectrical means including the respective switches LS1 and LS2 adaptedto be closed by upwardly-movable, downwardly-spring pressed, dependentrods 63 an 64 respectively which normally extend downwardly far enoughso that the switches LS1 and LS2 will be closed when the upward pressureof the fabric on bot-h rods is enough to assure that the elements 43 and44 will effectively press down upon the fabric.

In order to blow air upon and thru the uppermost piece of fabric (aswhen it has been stretched by the rotation of elements 43 and 44 or atsome other desired stage, as for example on release of one or both ofthe gripping means), there is provided blower means comprising, in thepresent instance, a source'of air under pressure, pipes 65 and 66, anddownwardly-and-inwardly-directed discharge openings 65a and 66a,respectively.

As exemplified, the table 41 is provided with an adjustable air-cushionsupport by means of a piston having a head 67 in an air cylinder 68. Airunder a cushioning pressure (of, e.g., eight pounds per square inch) isintroduced below the piston from a pipe 69 controlled by a normallyclosed valve 70, and above the piston head by a pipe 71 controlled by anormally closed valve 72 and connected with a normally closedpressure-relief valve 74 having an adjustable bleeder end 75 which, asexemplified, is adjusted for total opening of the pipe 71. As will beseen, when the valves and 74 are opened, the table 41 will be movedupwardly. The setting of the bleeder end should be such that the airabove the piston head 67 will be exhausted at least fast enough (muchmore than fast enough, as exemplified) to compensate for the removal ofthe fabric pieces one-by-one from the stack 39 and to cause the table torise between one movement of the pick-up head to position X and asuccessive (but not necessarily immediately successive) such movementthereof at least enough to bring the now-uppermost layer to a positionin the general vicinity of the position which a recently removed layerhas occupied. When, as exemplified, the table moves upwardly at a speedfaster than enough to compensate for the removal of the fabric pieces,the upward movement will open a limit switch 76 to close the valves 70and 74 (while the valve 72 and a normally closed relief valve 77 frompipe 69 remain closed) when the upper surface of the uppermost layer offabric on the stack moves the switch arm 78 of the switch 76, which armis set to move when the fabric has compressed to a desired degree underit. Thus, as fabric pieces are removed, the table 41 and the stack 39will rise whenever the upward pressure on the switch-arm 78 issutficient to operate the switch 76, so as to bring additional fabricpieces one-by-one to the same horizontal plane or to occasionally bringthe top of the stack to the general vicinity of such a plane (as may bedesired) for convenient pick-up by the head and withdrawal by thewithdrawal means comprising the beam 12 and the head 20. Some depressionof the top layer of the stack by the gripping means is desirable inorder for them to grip the fabric effectively, so that the switch arm 78should be arranged to be operative only when the top of the stack liesabove the lowest position of the pick-up elements. In the presentinstance, action of the limit switch 76 is replaced, or substituted for,in a part of a cycle before the head 20 depresses the top of the stack,by the activation of a switch 79 by a cam 79:: on shaft 25, which switch79 performs a similar function to the function of the switch 76, but isindependent of the action of the height of the stack.

When the table itself rises to an extent such that all or most of thefabric pieces of a stack thereon have been removed therefrom, the table41 will contact a limit switch 80 to open valve 72 and relief valve 77(which has a controlled bleeder end 81 similar to the end 75), and toclose valves 70 and 74, to permit the piston and table to drop undercontrol of valve 81 to a position wherein a new stack, such as thatshown at 39a, may be placed on the table. The activation of the limitswitch 80 also causes the circuit of the motor 29 to be broken todiscontinue movement of the beam 12. The switch 80 should be operativewhile there is still some depressible support, such as the cushion 42 ora few fabric pieces, between the table and the operative position of thejaws. As soon as the new stacks 39a is properly in place on the table, apush button 32 may be pressed to operate a switch PBI to restore thevalves to their normal positions and to cause the circuit of the motor29 to again be closed. An additional push button 83 may be provided toclose a switch PB2 to perform the function of the switch 80 whennecessary at any time.

The pipes 69 and 71 are supplied thru a pipe 85 when a gate valve 86 isopen. Pipe 85 extends to a main airpressure supply line 87 which alsosupplies a pipe 88 when a gate valve 89 is open. The pipe 88 has twobranches one of which is controlled by a switch 91. These branches areshown at 92 and 93; the latter being the one controlled by the switch91. Air fiows thru pipe 92 to pipes 65 and 66; this air discharge beingtimed to occur, in the exemplified operation, at a time when the head isabout to lift the uppermost fabric piece. The branch 93 is controlled bya normally closed valve 94 which is opened in response to the closing ofa switch 91 by crank arm 24 to pipe 92. At a time under control of valve94 air is blown thru pipe 93 to discharge nozzle 95 which directs airdownwardly upon a fabric piece released in a particular one of themanners hereinafter described as it is moved beneath the nozzle 95 by aconveyor to arrange and smooth the fabric piece as it passes thereunder.In the operation in question (hereinafter further described) the fabricwill now carry a small flap 96, formed by the pinching action of thegripping means and now pointing rearwardly of the direction of movementof a conveyor surface on which the fabric piece lies; and the jet of airfrom the nozzle 95 is first ejected after the rear (free) end of theflap 96 has passed beneath the nozzle, so that the spreading fan of airabove the surface will bend the flap forward and straighten and smooththe fabric.

The air pressure normally provided beneath the piston head serves as acushion which yields as the head 20 swings into contact with the top ofthe stack, and facilitates the gripping of the top layer withoutgripping the second layer.

The air flow thru pipes 65 and 66 is distributed to the openings 65a and66a, respectively, thru chambers 97 and 98.

In FIGS. Sta-8i there is exemplified a two-cycle se quence of operationswhereby alternate ones of fabric pieces cut from a stack ofright-side-out circularly-knit tubular fabric interiorly of the edgesthereof are trans ferred to a conveyor with the same side up as whenthey were in a stack, whereas the intervening ones are turned over inthe process of being transferred to a conveyor, so that all the pieceswill be the same side up when they are on the conveyor, to have abinding tape sewn to the uniformly uppermost right side thereof, forexample. In cycle 1, exemplified in FIGS. 8a8d, the relays 53 and 54 aresubstantially simultaneously energized when, because of the nature ofthe stack and the small areas of the ends of the rods 63 and 64 inrelation to the lower surface portions 57 and 58 of the rotary elements43 and 44, the surface portions 57 and 58 are in sufiiciently firmengagement with the fabric to move the (end) edge portions of the fabricaway from each other, by movement of the portions 57 and 58 toward theirrespective edges. As the upper fabric piece 38 becomes pinched by thegripping means 33 and the gripping means 34, the rotation of the crankarm causes the head 20 to swing past a curving bafiie plate 99 and abovea conveyor 100 (which has a higher coefiicient of friction than thefabric). When the head is above the conveyor (near the beginning of itsreturn movement, as exemplified), the solenoid 54 is de-energized andthe solenoid 56 energized to swing the surface portion 58 inwardly awayfrom the surface 62 to release the grip of the gripping means 34 on theforward portion of the fabric piece 38 and allow the released end of thefabric piece to contact the surface of the conveyor which tendsto carryit forward in the direction of the arrow. The rear end of the piece 38is still held by the gripping means 33, but is released thereby afterthe just released forward end of the piece has dropped on the conveyor.In cycle 2, exemplified in FIGS. 8e8j, the fabric piece 40 is picked upthe same way as the fabric piece 38, but its forward end is released bythe gripping means 34 early enough so that this end will fall on thestationary baffle plate 99 (rather than conveyor 100) by which bai'iieplate the fabric piece 40 will be turned over before it reaches theconveyor 100. The gripping means 33 releases the rear end of the fabricpiece while this rear end is over the conveyor and before the forwardend reaches the conveyor, so that the fabric piece 40 will now lieupside down on the conveyor. The flap 96 may be flattened out asindicated above.

In order to space the pieces of fabric evenly, the release of each piece38 by the gripping means 33 is postponed until it is spaced rearwardlyof a preceding piece 40 the same amount that a succeeding piece 40 willbe spaced from it. The release of the fabric piece 38 (in cycle 1)accordingly does not occur until the head 20 has started its returnmovement (see FIGS. 80 and 8d).

In order to open the respective valves 94, 72, 77, 70, and 74, there areprovided solenoids 101, 102, 103, 104, and and there is provided asolenoid 106 to open a valve 107 to admit air thru a pipe 108 to anozzle 109 positioned to discharge air laterally over a point on theconveyor (beyond the nozzle 95) where a rufiied fabric is detected by aphotoelectric cell device 110-111 to close a limit switch LS9 toenergize solenoid 106, so as to blow off from the conveyor any piece offabric which has been picked up or deposited improperly to such anextent that the fabric piece does not lie sufiiciently flat on theconveyor to be properly received by a sewing machine 112 or other fabrichandling or treating device.

Flow thru the pipes 65 and 66 is, respectively, controlled by valves 115and 116 operated, respectively, by solenoids 123 and 124.

In addition to the cam 79a for operating the switch 79, the shaft 25carries a cam 131 for operating switch 91 to actuate solenoid 101, thecams 133 and 134 to actuate switches LSA and LSB which energizesolenoids 123 and 124, respectively. Driven by belt 135 from shaft 25 athalf the speed thereof is a shaft 136 carrying cams 137, 138, 139, and140 which open normally-closed switches LSA1, LSBl, LSA2, and LSB2.Switches LSBl and LSAI actuate solenoids 56 and 55, respectively, in thefirst operating cycle, whereas these respective solenoids are oper- 7ated by switches LSB2 and LSA2 in the second operating cycle; and all atpoints in the cycle as indicated in detail in FIG. 11, and all asfurther described hereafter.

The operating voltage for the unit is connected to parallel lines 200and 201 between which are connected in series lines 213214-215216. Thetwo switches, LS1 and LS2, are connected in series in line 215. There isplaced in parallel with switches LS1 and LS2 a set of normallyopencontacts 216a operated by a relay CR1, which is connected across thecoil of solenoid 53. These units are fed by lines 216 and 201. Releasecoil 55 in a line 217 is controlled by a normally-closed set of contacts217a operated by relay CR1. These components are connected by lines200217201. The release of the first sequence is controlled by the twonormally closed limit switches, LSA1 and LSA2. These are connected bylines 200-213 214. The purpose of this portion of the circuit is tocontrol at a regulated squence the pickup and release of a piece offabric by the activation and subsequent deactivation of the grippingmeans 33. The two solenoids 53 and 55 are so connected into the circuitthat the energization of the solenoid 53 will cause the element 43 torotate in a clockwise manner (FIG. 5) and the energization of therelease coil 55 (after the de-energizing of the coil 53) will rotate theelement 43 counterclockwise.

The actuating rods 63 and 64 of limit switches LS1 and LS2 are,respectively, placed adjacent to the pick-up means 33 and pick-up means34. When both switches are closed pressure of the fabric against therods, current is allowed to energize coil 53 and relay CR1. The closingof relay CR1 closes CR1 contacts 216a shunting limit switches LS1 andLS2, and thus locking the circuit in. Element 43 has rotated and is nowholding the fabric. At the instant CR1 coil and coil 53 are activated,the (CR1) normallyclosed contacts 217a open, allowing the coil 55 todeenergize. The function of limit switches LSAl and LSA2 (in the nextstep of the circuit) is to release the pick-up coils 53 and 54 at theappropriate time as called for by the .position of cams 137 and 139,respectively, that strike and open these limit switches.

Line 200 connects to normally closed contacts LSBl and line 219 connectsnormally-closed contacts LSB2 to LSB1. Line 200 connects contacts LSB2to (CR1 normally-open) contacts 220a. The other side of contacts 220a ofCR1 are connected by line 221 to pick-up coil 54 in parallel with relaycoil CR2. Both these coils are connected to line 201. Line 200 connectsto normally closed contacts 221a or CR2 relay, the other side beingconnected by line 222 to release coil 56. The other side of the coil 56is connected to line 201. In the control of pickup means 34 and itsrelease, the operation is similar to that of pick-up means 33 except forthe means of actuation. When hold-in coil CR1 is energized by theclosing of limit switch LS1 and limit switch LS2, the act ofnormally-open contacts 22011 of CR1 relays are closed allowing currentto flow and energize pickup coil 54. Further, coil CR2 is alsoenergized.

As above indicated, in order that a more positive detachment may beobtained, compressed air may be employed. Air jets 65a and 66a arerespectively placed in close proximity to pick-up devices 33 and 34.These jets are independently controlled solenoids 123 and 124,respectively. The sequence of opening and closing solenoids 123 and 124are controlled by cams 133 and 134 respectively, opening the normallyclosed limit switches LSA and LSB or permitting them to close.

In order to obtain the desired amount of air for either cycle, a timeris used, the function of which is to control the length of time thateither of solenoids 123 and 124 are to remain open. Limit switch LSA isconnected by line 200 and is parallel with a set of hold-in normallyopencontacts 222a on a relay CR3. Line 23 connects to relay CR3. Thenormally-closed contacts 222k of a time delay relay, of relay CR3TD isplaced between line 223 and a line 224 which connects, in parallel, thecoil of relay CR3, the solenoid coil 123, and the coil of the time delayrelay CR3TD. The other side of all three coils are interconnected byline 201.

Upon closing of LSA by the action of the cam 133 on this limit switch,current is allowed to flow thru the circuit and energize the coils CR3(solenoid) 123, and CR3TD. The normally-open contacts of CR3 immediatelyclose, thus shorting out the normally-open contacts of LSA, and thusallowing the flow of current to continue thru the circuit. At the sametime that CR3 coil and solenoid 123 coils were energized, CR3TD, whichis the time delay coil, is also energized. Upon conclusion of the timeset on CR3TD time delay coil, its contact 222!) situated between lines223 and 224 will open, thus disconnecting this circuit and setting it upfor the next cycle.

Limit switch LSB with normally opened contacts is activated by earn 134.Across the normally-open contacts LSB there is placed in parallel a setof normally-open contacts 224a of a relay CR4 which are connected bylines 200 and 225. CR4 hold-in coil is connected in parallel with thecoil of the solenoid 124, and the coil of the time delay relay CR4TD, byline 201 and a line 226. The normally-closed contacts 226a of CR4TD timedelay relay completes the circuit by being connected to lines 225 and226. The function of this circuit is identical to that as described forthe circuit required to operate solenoid 123.

Lines 200 and 201 have inserted therebetween a line 228 containingnormally-open switch 91 and solenoid 101 for closing valve 94. Betweenlead 200 and a conducting element 229 there are connected in parallelclosable normally-open contacts PBZ under control of push bupton 83;normally open hold-in contacts 229a of coil CR t and closable normallyopen contacts of tabledown hold-in switch and from element 229 to lead201 in parallel solenoid 102, solenoid 103 and line 230. Line 230contains the coil CR6 in addition to a normally closed switch PB1openable by push button 82. Thus, the closing either of switch 80 or ofswitch PB2 operated by push button 83, will not only open valves 72 and77, but will also energize coil CR6. The energization of coil CR6 willclose contacts 229a of CR6 and will at the same time open normallyclosed contacts 23% of CR6. A line 235 contains the normally-closedcontacts 230s of CR6 and a coil CR7. When switch PB1 is opened coil CR6is deenergized, thus allowing its contacts 230C to close and energizecoil CR7.

Connected to lead 200 are normally open contacts 235a of CR7, the otherside of which are connected by line 236 to one side of the motor, theother side of the motor and line 201 being interconnected to another setof normally open contacts 236a of CR7 by line 237 completing the circuitthru the motor. Thus, the opening of switch PB1 will result in startingup the machine again, as well as in permitting the closing of valves 72and 77.

Solenoids 104 and 105 are in parallel lines respectively running to lead201 from line 2371: running from lead 200 and containing anormally-closed switch 230b (which is opened by the energization of coilCR6), switch 76 and switch 79; and, thus, valves 70 and 74 will be openonly when switch 230]) is in its normally closed position and whenswitches 75 and 79 are also held in their normally closed position.

In the event of a poor pick-up and subsequent deposit of fabric on theconveyor, the ruffled piece of fabric is detected by photoelectricdevice -111 to close limit switch LS9, which energizes solenoid 106,causing a laterally-directed jet of air to remove the piece of fabric inquestion. Line 200 connects to the normally open contacts of limitswitch LS9, which interconnects with solenoid 106 by line 238. Solenoid106 is connected to line 201 to complete the circuit thru solenoid 106to pass air thru said nozzle 109.

Various features set forth in our copending application Ser. No. 412,103may be incorporated in mechanism embodying the present invention.

tion or shown in the accompanying drawings shall be in- I terpreted asillustrative and not in a limiting sense.

We claim:

1. Mechanism for separating pieces of fabric from a stack thereofcomprising means to engage and exert frictional pressure on the uppersurface. of the top piece of a stack near each of opposite edges of thepiece, and means to move'an engaging portion of each engaging meanstoward its respective edge while exerting said frictional pressure tostretch the upper piece of fabric therebetween and thereby loosen itsengagement with the piece below it, wherein each of said engaging meansis formed with a fabric-engaging portion having a convexlongitudinallyextending fabric-engaging frictional pressure surface andwherein said moving means is arranged to move said surfaces along curvedpaths.

2. Mechanism as in claim 1 wherein a fabric-pinching means is associatedwith each of said engaging means and wherein during the action of saidmoving means each of said pinching means is disposed with an operativesurface slightly spaced inwardly from its one of said edges and slightlynearer said one of said edges than its associated frictional pressuresurface and adapted to cooperate with said associated frictionalpressure surface to grip fabric therebetween when said engaging meansare moved by said moving means.

3. Mechanism for separating pieces of fabric from a stack thereofcomprising means to engage the upper surface of the top piece of a stacknear each of opposite edges of the piece, means to move an engagingportion of each engaging means toward its respective edge to stretch theupper piece of fabric therebetween and thereby loosen its engagementwith the piece below it, a pair of fabricgripping means each comprisingone of said engaging means, stack supporting means, means for mountingsaid gripping means, means operative after said moving means to cause arelative separative movement of said supporting means and said mountingmeans for effective relative separative movement of an engaged piece andthe stack, means for releasing said gripping means, and means includingthe releasing means and means controlling the timing thereof fordepositing a fabric piece with the same side up a when it was on the topof the stock and for depositing another fabric piece with the oppositeside up than when it was on the top of the stack.

4. Mechanism as in claim 1 wherein each of said gripping means comprisesa gripping element having a convex fabric-engaging frictional surface,and wherein said gripping elements are rotatable on parallel axes bysaid moving means.

5. Mechanism for transferring pieces of fabric from a stack thereofcomprising a pair of relatively widely spaced rotatable grippingelements each having an axiallyextended convex fabric-engagingfrictional surface, means having gripping surfaces spaced at a greaterdistance apart than the first-mentioned surfaces and relatively slightlys aced from said first-mentioned surfaces to provide therewithfabric-gripping means when said first-mentioned surfaces are rotated,means to move saidgripping elements against the uppermost piece offabric on a stack and to rotate said gripping elements, means to supporta stack of fabric pieces, means to cause a separating action of saidgripping elements and said supporting means after the operation of saidrotating means, and means for effecting controlled releasing operationsof said gripping elements.

6. Mechanism for transferring pieces of fabric from a stack thereofcomprising a stack support, a conveyor, draw-over means between saidconveyor and the position of a stack on said stack support, means topick up a 10 piece of fabric from the top of the stack at a positiontoward said conveyor and means to pick up said piece of fabric at aposition remote from said stack support, means to operate both saidpick-up means, means to move both said pick-up means from a position inproximity to said stack to a position in which they are over saidconveyor,

means to release the first-mentioned pick-up means when it is over saidconveyor, means to thereupon release the second-mentionedpick-up means,means to return both said pick-up means and to operate them again, meansto .cause a repeated operation of said means to move both said pick-upmeans from a position in proximity to the stack to a position in whichthey are over said conveyor,

means to release the first-mentioned pick-up means before a piece heldby said second-mentioned pick-up means is drawn over said drawn-overmeans, means to release the second-mentioned pick-up means when it isover said con veyor, and means to thereupon return both said pick-upmeans.

7. Mechanism for transferring pieces of fabric from a stack thereof to areception means, comprising means to pick up a piece of fabric from thetop of a stack and t0 deposit it with the same side up as when it was onthe top of the stack and to pick up a succeeding piece of fabric fromthe top of the stack and to deposit it with the opposite side up thanwhen it was on the top of the stack, said pick-up means comprising meansto engage the upper surface of the top piece of a stack near an edge ofthe piece, means to engage the top piece of a stack at a place spacedfrom the aforesaid means, and means to move an engaging portion of atleast one of the engaging means away from the other of said engagingmeans to stretch the upper piece of fabric therebetween and therebyloosen its engagement with the piece below it.

8. Mechanism for transferring pieces of fabric from a stack thereof to areception means, comprising means to pick up a piece of fabric from thetop of a stack and to deposit it with the same side up as when it was onthe top of the stack and to pick up a succeeding piece of fabric fromthe top of the stack and to deposit it with the opposite side up thanwhen it was on the top of the stack, said pick-up means comprising apair of pick-up elements, and means to operate said pick-up elements topick up a fabric piece at the same time and to release it at differenttimes.

9. Mechanism for transferring pieces of fabric from a stack thereof to areception means, comprising means to pick up a piece of fabric from thetop of a stack and to deposit it with the same side up as when it was onthe top of the stack and to pick up a succeeding piece of fabric fromthe top of the stack and to deposit it with the opposite side up thanwhen it was on the top of the stack said pick-up means comprising a pairof pick-up elements rotatable on parallel axes and each having a convexaxially-extending frictional surface, and means to rotate said pick-upelements at the same time and to release them at different times.

10. Mechanism as in claim 9 wherein said releasing means is arranged torelease one of said pick-up elements at an earlier time after it haspicked up each of certain of the fabric pieces and at a later time afterit has picked up each of other of said fabric pieces.

11. Mechanism for transferring pieces of fabric from a stack thereof toa reception means, comprising means to pick up a piece of fabric fromthe top of a stack and to deposit it with the same side up as when itwas on the top of the stack and to pick up a succeeding piece of fabricfrom the top of the stack and to deposit it with the opposite side upthan when it was on the top of the stack, said pick-up means comprisinga pick-up element having a convex axially-extended frictional surfaceadapted to move in one direction for a pick-up operation and in theother direction for the release operation, and means for causingmovement of said pick-up element in the first direction when 1 1 saidsurface is in engagement with a piece of fabric at the top of the stackand in the other direction when said surface is at a remote point.

12. Mechanism for transferring pieces of fabric from one position toanother position which comprises pick-up means operative on one portionof a fabric, pick-up means operative on another portion of a fabric,means to cause both said pick-up means to pick up a fabric with one ofits sides up, means to deposit a thus-picked-up fabric with said side upand including means for eifectuating a particular timing of the releaseof at least one Of said pick-up means, and means to deposit athus-picked-up fabric with an opposite side up and including means foreffectuating 12 a different timing of the release of at least one ofsaid pick-up means.

References Cited UNITED STATES PATENTS 793,009 6/1905 Miller 27118850,313 4/1907 North 271-65 2,256,852 9/1941 Schubert 27162 X 2,799,4997/1957 Perry et 'al. 271-26 3,083,961 4/1963 Arbter 271- 33 3,168,3072/1965 Walt0n 'et a1. 271-26 3,176.979 4/1965 Engelmann 27118 ALLEN N,KNOWLES. Primary Examiner.

8. MECHANISM FOR TRANSFERRING PIECES OF FABRIC FROM A STACK THEREOF TO ARECEPTION MEANS, COMPRISING MEANS TO PICK UP A PIECE OF FABRIC FROM THETOP OF A STACK AND TO DEPOSIT IT WITH THE SAME SIDE UP AS WHEN IT WAS ONTHE TOP OF THE STACK AND TO PICK UP A SUCCEEDING PIECE OF FABRIC FROMTHE TOP OF THE STACK AND TO DEPOSIT IT WITH THE OPPOSITE SIDE UP THANWHEN IT WAS ON THE TOP OF THE STACK, SAID PICK-UP MEANS COMPRISING APAIR OF PICK-UP ELEMENTS, AND MEANS TO OPERATE SAID PICK-UP ELEMENTS TOPICK UP A FABRIC PIECE AT THE SAME TIME AND TO RELEASE IT AT DIFFERENTTIMES.